European Pat. No. 96,296 discloses a group of 3-iminoacetamido-azetidinone-1-sulfonic acid derivatives with broad spectrum antibacterial properties. Among the substitutional variations embraced at 4-position are the hydroxyiminomethyl and loweralkoxyiminomethyl groups.
Sendai et al., J. of Antibiotics 38 346 (1985), in an attempt to improve the antibacterial activity of sulfazecin, studied various modifications at the 3- and 4-positions, ultimately selecting (3S,4S)-3-[2-(2-aminothiazol-4-yl)-(2)-2-carboxymethoxyiminoacetamido]-4-c arbamoyloxymethyl-2-azetidinone-1-sulfonic acid as presenting the best activity profile. Several acyloxymethyl substituents in the 4-position were studied, including the acetoxy-, carbamoyloxy-, benzoyloxy-, methylsulfonyloxy-and 2-thienylacetoxy-methyl groups, with the carbamoyloxy methyl substituent being the most efficient 4-substituent found.
Noguchi et al., J. of Antibiotics 38 1387 (1985) extended the study of 4-position substitutional variations of sulfazecin to explore the 4-acetoxy, methylsulfonyl, various substituted thio groups, azido and triazolyl groups. The 4-carbamoylmethylthio substituent was the most active among the 4-substituted derivatives studied.